Most of modern electronic products or devices are very sensitive to the variations of operating temperatures. For example, the output performance of digital cameras will be influenced by the ambient temperature they are situated. For the inside of a chip IC, the variation of temperatures also influences the operating point and the operating speed. Thereby, in order of stable performance, most electronic devices usually need to have temperature sensors for detecting ambient temperature and compensating signals.
Currently, bipolar junction transistor (BJT) circuits are widely applied to temperature detecting circuits. The principle is to compare two voltage values both generated by BJTs. One voltage value is relevant to temperature; the other is irrelevant to temperature. Comparing the two voltage values gives the result due to temperature variation. By inputting the difference between these two voltage values, the digital code representative of temperature information can be given.
Nonetheless, the temperature sensor implemented by BJTs has lower sensitivity; it requires auxiliary circuits with higher accuracy, which results in increase in the complexity as well as costs of circuits. In addition, because BJTs are used, it is relatively difficult to operate at lower voltages. Consequently, the power consumption is increased.
Accordingly, the present invention provides a novel analog-to-digital converting circuit with temperature sensing and the electronic device thereof for solving the problems described above. Because the adoption of the auxiliary circuits with higher accuracy is avoided, the costs can be reduced. Besides, the power consumption is lowered and the resolution is enhanced. The problems described above are thus solved.